Water quality sampling system

ABSTRACT

A method and system are provided in which a water sensing device is equipped with a water-sealed sampling chamber enclosing the sensing probes of the sensing device. When the device is placed into its water habitat, water flow into and out of the sampling chamber is controlled such that water is present in the sampling chamber only during a relatively brief period of time when water quality measurements are taken by the probes. After the water quality measurements have been taken by the probes, the water sample is substantially pumped out of the sampling chamber so as to minimize the time during which the probes are in contact with the water being analyzed.

FIELD OF THE INVENTION

The present invention relates generally to water quality samplingsystems and more particularly to a system and apparatus for enablinglong term deployment of water quality sensor devices.

BACKGROUND OF THE INVENTION

For many reasons, water quality, and the monitoring and testing ofwater, has become a very important undertaking in today's environment.More and more bodies of water are being monitored for quality on aregular basis. Further, water samples are being taken, analyzed andrecorded for a greater number of locations within given bodies of water.

The water samples are taken and analyzed in order to determine residentamounts of various chemicals and biological elements. These measurementsare then logged into a database for subsequent planning purposes. Asvarious actions are taken to purify or de-contaminate the water,sampling-is again used to determine whether or not the water treatmentplans are effective.

Currently, all government and state agencies are monitoring waterquality using multi-sensor units called “multiprobes”.

The sensing devices or multiprobes are equipped with sensors to measuredifferent water quality parameters or characteristics such as, interalia, pH, dissolved oxygen, conductivity, salinity, temperature,turbidity, ammonia, nitrate, Oxidation Reduction Potential (ORP), andmany others. The sensor devices also include an electronic circuit boardin a water-sealed housing as well as a real time electric clock, analogand digital circuitry to control the operation of the sensors based upona real time schedule. The multiprobes or sensor units are continuouslysubmerged in water during the deployment time. Sediments and biologicallife in the water cause fouling of the sensors or probes and affect thesensor's performance and longevity.

In a typical application, a water sensing device is placed under waterat a location where the water is to be analyzed. Periodically, accordingto a programmed schedule, different measurements are taken by varioussensors or probes which are mounted at the end of the water sensingdevice within the water. These readings are stored in memory onboard thesensing device and periodically the sensing device is pulled from thewater and connected to a computer, for example a personal computer (PC)or laptop computer, where the readings that had been taken aretransferred from the sensing device to files on the PC for furtherprocessing, recording and distribution.

As hereinbefore noted, a main problem for this method of water testingis the fouling process which occurs because the water to be analyzed isin constant contact with the testing probes. As a result, sediments,biological life and other factors take their toll of the sensing probesand, over time, render the probes inaccurate if not ineffective. If thefouling problem is not corrected by cleaning the probes on a regularbasis, the readings taken by the sensing device are inaccurate andsometimes readings cannot even be taken rendering the water sensingdevice useless.

In the past, this problem has been corrected by physically removing thesensing device from its water habitat, and physically cleaning thesensors or sensing probes before re-installing the sensing devices totheir testing locations under water. However, this process is quiteexpensive and requires much manpower to keep the sensing probes clean sothat accurate readings can be taken and the readings can be relied uponin making water treatment plans.

Thus, there is a need for an improved processing system and apparatuswhich enables a longer term deployment of water quality sensing devicesand less frequent cleaning time for such devices.

SUMMARY OF THE INVENTION

A method and system are provided in which a water sensing device isequipped with a water-sealed sampling chamber enclosing the sensingprobes of the sensing device. When the device is placed into its waterhabitat, water flow into and out of the sampling chamber is controlledsuch that water is present in the sampling chamber only during arelatively brief period of time when water quality measurements aretaken by the probes. After the water quality measurements have beentaken by the probes, the water sample is substantially pumped out of thesampling chamber so as to minimize the time during which the probes arein contact with the water being analyzed.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present invention can be obtained when thefollowing detailed description of a preferred embodiment is consideredin conjunction with the following drawings, in which:

FIG. 1 is an illustration of a prior art water sensing device;

FIG. 2 is an illustration of a water sensing device including anexemplary implementation of the present invention;

FIG. 3 is a schematic block diagram of the major electronic componentsof a circuit board utilized in an exemplary operation of the watersampling chamber portion of the water sensing system;

FIG. 4 is a schematic block diagram of the major electronic componentsof a personal computer which may be interfaced with the water samplingchamber portion of the illustrated sensing device;

FIG. 5 is an illustration of an exemplary graphical user interface whichmay be used in connection with the present invention;

FIG. 6 is a timing chart illustrating the relative timing betweenvarious functions operating in a water sampling cycle; and

FIG. 7 is a flow chart illustrating an exemplary sequence of operationsin a cyclic operation of the water sampling chamber portion of theillustrated sensing device.

DETAILED DESCRIPTION

It is noted that circuits and devices which are shown in block form inthe drawings are generally known to those skilled in the art, and arenot specified to any greater extent than that considered necessary asillustrated, for the understanding and appreciation of the underlyingconcepts of the present invention and in order not to obfuscate ordistract from the teachings of the present invention.

With reference to FIG. 1, there is shown a prior art water sensingdevice 101 positioned in a normal deployment mode below the surface 103of a body of water at a point where the water is to be measured andanalyzed. The sensing device 101 includes sensing probes 105, 107 and109 for sensing various characteristics of the water surrounding theprobes. In the example, only three probes are shown for simplicityalthough the exact number of probes for any application will varydepending upon the characteristics of the water which are being sensed.When the sensing device 101 is deployed under water as shown, the probes105, 107 and 109 are in constant contact with the surrounding water. Theprobes 105, 107 and 109 are connected to a circuit board 111 whichcontains water analysis electronics. The sensing device 101 alsoincludes connection means 113 for electrically connecting the sensingdevice 101 to a computer system such as a laptop or personal computer(PC), both while the sensing device 101 is in the water and also whenthe device is removed from the water for cleaning and/or maintenance.

FIG. 2 illustrates a sensing device 201, circuit board 211, probes 205,207 and 209 and connecting electrical cable 213. The device 201 is showndeployed below water level 203. The device 201 also includes a watersampling module 221 in accordance with the present invention. It isnoted that there are several functions of the water sampling operationof the present invention which may be synergistically shared with thewater sensing device 201, and the present invention may be implementedin either form, either as an attachable portion or module to the sensingdevice 201, or as an integral part of a water sensing device 201. Whenthe module is manufactured as an integral part of the water sensingdevice 201, the device clock may be used as a system clock and asynchronization function within the sampling module will not be needed.Further, the circuit board described herein as part of the samplingmodule 221 may be directly implemented into the circuit board of thesensing device 201 and, in that case, the valve, hold and pump-outfunctions of the sampling module can be directly controlled from themodule control circuitry, whether it is integrated into the sensingdevice board 211 or as a stand-alone board 231 as shown in the presentexample.

The sampling module 221 in the present example contains severalsections. A sample or sampling chamber 222 is shown connected to thelower portion of the sensing device 201 and placed so as to enclose theprobes 205, 207 and 209 of the device 201 within the sampling chamber222. The sampling chamber is totally water-sealed from the surroundingwater and from the water sensing device 201 and the lower sections ofthe module 221, except for a water inlet 247 for allowing water to flowinto the chamber 222, and a water outlet 248 for allowing water to beevacuated from the chamber 222 at the proper times as is hereinafterexplained in greater detail. The sampling chamber 222 also has an airvent 252 which is allowed to vent to outside air through air vent tube253. Outside air moves through the air vent into the chamber when wateris being pumped out of the chamber 222, and air is forced through theair vent 252 to outside air supply as water is allowed to fill thesampling chamber 222. A second or component section 229 of the samplingmodule 221 contains a valve device 233, a pump 235 and a circuit board231. The second section is also water sealed from the surrounding water.A third section 239 of the sampling module 221 is open to surroundingwater at the bottom and through holes 242. The third section 239 acts asan interface to the surrounding water to selectively allow water toenter the sampling module through the filter material 241.

In operation, at a designated time prior to a time when the probes 205,207 and 209 are powered-up take readings, valve 233 is opened and watersurrounding the lower portion of the module 221 enters the modulethrough the bottom section as shown 243 and it is filtered by filtermaterial 241 before passing through a conduit 245 and the valve 233 tothe sampling chamber 222. When the valve 233 is opened, the water to besampled is allowed, through hydrostatic pressure, to pass throughconduit 246, enter and eventually fill-up 237 the sampling chamber 222as indicated 227 in the drawing, surrounding the probes 205-209. In thepresent example, the valve is opened for a predetermined first timeperiod sufficient to allow the sampling chamber 222 to fill. After thefirst time period, the valve is closed and measurements are then takenby the probes 205-209. The valve 233 remains closed for a second timeperiod to allow sufficient time for the probes 205-209 to takemeasurements of the water in the sampling chamber 222. After the secondtime period has expired, the pump 235 is turned ON for a predeterminedthird period of time, i.e. a pump ON time, and the sampled water ispumped through outlet 248, conduit 249, pump 235 and conduit 250 to adischarge line 251 and then to the outside water surface 203. In thepresent example, the sampled water is discharged to the water surfaceaway from the water inlet area 243 so as not to disturb the watersurrounding the inlet area 243 and also to prevent re-reading the samewater samples. After the passage of the third period of time the pump235 is again turned OFF until the next scheduled reading cycle. Otherspecific schemes may be implemented to enable water to enter and exitthe sampling chamber at the proper time. For example, water may bepumped into the chamber rather than allowed to enter by means ofhydrostatic pressure as is shown in the illustrated example. Also, waterlevel detectors may be implemented, for example, to determine when thesampling chamber is filled and/or emptied so as to close the valve andturn OFF the pump instead of controlling the valve and pump operationsusing predetermined time periods. Further, the initialization and timereferences for the filling, holding and evacuating of the samplingchamber may be taken directly from the clock on-board the circuit board211 of the water sensing device 201 rather than synchronizing a clock onthe circuit board of the sampling module 221 as is shown in the presentexample. In any implementation however, the present invention will bepracticed by providing a sampling chamber containing water readingprobes for a water sensing device and then controlling the flow ofsampled water into and out of the chamber such that the probes areexposed to the water for only limited periods of time while readings arebeing taken by the probes.

FIG. 3 is a schematic diagram of the major components of an exemplarycircuit board 231 within the sampling module 221. As shown, the boardcontains a main interconnection bus 301 arranged to connect the variouscomponents of the board together. The bus 301 is connected to a CPU 303or other main controller, and a memory device 305 which may comprise,for example, a flash memory unit. The memory 305 may be used to storeoperational programming for controlling the operation and timing of thesampling module 221. Also, connected to the bus 301 is a local clock307, and a clock battery 309. In the present example, the on-board clockbattery 309 is used to power only the clock and power for the othercomponents on the board is provided from an external power supplythrough connector 315. The board also contains valve control and pumpcontrol components for controlling water input to the sampling chamber231 through the valve 233 and water being evacuated from the samplingchamber 231 by the pump 235. The board also has a connector 317 forconnecting the sampling module circuit board 231 to an external computersystem, which may be a PC or laptop computer, for uploading anddownloading information and also for testing purposes.

FIG. 4 is a schematic diagram showing the major components of a computersystem, e.g. a PC, to which the sampling module circuit board 231 or thesensing device circuit board 111 may be connected. As shown, thecomputer system includes a main interconnection bus 401 arranged toconnect the various components of the system together. The bus isconnected to a CPU 403, a memory unit 405, a PC clock 407, a storagesystem 409, an input system 411, a display unit 413, a power supply 415a media drive 417 (such as a CD drive) and a network interface 419 forproviding a connection to a network of computers which may beimplemented in a larger water monitoring system. The PC also includes aconnector 421 to the sensing device 101 and also to the sampling module221. As hereinbefore discussed, where the electronics of the samplingmodule 221 and the sensing device 101 are integrated together, only oneelectrical connection, e.g. 421, will be required, although asillustrated in the present example, separate electrical cables are used,one each for the sensing device 101 and the sampling module 221. Otherdevices and components may also be connected to the main bus 401depending upon particular applications.

FIG. 5 illustrates an exemplary graphical user interface (GUI) 500 whichmay be used to schedule operations of the sampling module 221. As shown,a schedule and setting screen is presented on a display of the PCconnected to the sampling module circuit board connector 317. The dateand time 503 as contained in the memory of the sampling module 221 isdisplayed as well as the date and time 505 as contained in the clocksystem of the connected PC. By “pointing-and-clicking” amouse-controlled pointer (e.g. 519) on the button 507 on the displayscreen or GUI 500, a user is enabled to update the module clock 307 to adesignated reference which may be the clock on-board the sensing device101/201. Another button 509 enables the user to synchronize the moduleclock 307 to the PC clock 407. In the example, the PC clock is also usedto synchronize to the sensing device clock so that both the sensingdevice clock (not shown) and the sampling module clock 307 are insynchronization. This synchronization is an important step since thesensing device will be programmed to take readings at predeterminedtimes and the operation of the sampling module must be coordinated suchthat when readings are taken by the probes 205-209, the sampling chamber222 is filled with water, and the water is promptly evacuated from thesampling chamber after such readings have been completed. For example,the probes are generally programmed to take a measurement or readingevery 15 minutes, 30 minutes or 60 minutes. The probes have to bepowered-up for 2 minutes before taking a measurement or reading. Whennot taking measurements, the probes are dormant and are not powered-upin order to conserve power. If it takes, for example, 2 minutes to fillthe sampling chamber with water, then the filling process i.e. theopening of valve 233 will need to begin prior to the time the probes arebeginning to power-up in order to allow time for the water in thesampling chamber 222 to settle prior to taking measurements by theprobes 205-209. Further, the pumping-out of the water from the samplingchamber 222 cannot begin until after the probes 205-209 have completedtaking measurements. Thus, it is apparent that the operation of thesampling module 221 and the operation of the sensing device probes mustbe coordinated and synchronized.

The GUI 500 also includes a scheduling table 511 for displaying activeand inactive schedules for the operation of the sampling module 221. Anactive-schedule 513 is one which has been activated and represents acurrent operating schedule for the sampling module and an inactiveschedule is one which is not currently active. A schedule includesindications for the date and time for when the schedule is started andalso the date and time for when the schedule is stopped as well as theinterval or time between sampling operations. In a scheduling portion515 of the GUI 500, a user is enabled to create a schedule by indicatingstart and stop dates and sampling interval. After inputting values forthese selections, a user is enabled to ADD the schedule to the table 511by pointing-and-clicking 519 on an ADD button 517. If a user selects“Custom” from the Select Interval section, the user is enabled todesignate a Custom Schedule 521 including custom times for the samplingchamber operation. In the illustrated example, an Interval time periodof 15 minutes 523, an Open Valve time period of 2 minutes 525, a SampleHolding time period of 1 minute 527 and a Pump ON time period of 1minute are shown. These may also represent default time periods whenspecific time periods are not input. The GUI 500 also indicates theBattery Voltage. Other buttons enable a user to Clear All Schedules andto Save the input information and scheduling to the memory unit 305 ofthe sampling module 221. The GUI may be exited by pointing-and-clickingon the EXIT button 531.

At the designated intervals, for the time periods designated above forexample, each sampling module operation consists of opening the valve233 for 2 minutes, closing the valve and holding the sampling chamberclosed for a period of 1 minute while the probes take measurements(typically in the middle of this 1 minute period), and then pumping235-the sampling chamber water out of the chamber through the sampledischarge line 251 for a time period of 1 minute. After pumping-out thesampling chamber, the probes are maintained at a “just moist”environment to keep the probes hydrated during the down time betweenmeasurements. The amount of water remaining in the sampling chamber 222between measurements may vary depending, inter alia, on the pump-outtime period, so long as the sampling chamber is substantially evacuatedand the probes are not immersed in water when measurements are not beingtaken. As shown in FIG. 6, when it is time to begin a probe measurementcycle, the probes begin to be powered-up 601. In the example, thisprocess takes 2 minutes. Since before measurements can be taken by theprobes, the sampling chamber must be filled, the Open Valve Period (OVP)is initiated 603 prior to the time the probes are beginning to bepowered-up. According to the scheduled cycle, the OVP period lasts for 2minutes and is completed 605 prior to a time when the measurements aretaken by the probes 607. When the OVP is completed, the holding period(HP) is initiated 605 during which time the valve 233 is closed andwater is held in the sampling chamber 222 while the probe measurementsare taken 607. The holding period begins 605 prior to the time themeasurements are taken and ends 609 after the measurements are taken bythe probes 607. After measurements are taken, the probes are powereddown 611 to await the next sampling cycle and the holding period ends609 while the Pump ON period begins and turns ON the pump to empty thesampling chamber 222. After 1 minute, the Pump ON period ends 613, thesampling chamber has been emptied and the pump 235 is turned OFF.

FIG. 7 is a flow chart showing an exemplary sequence of operation forthe sampling module 221. The process begins when it is determined byreference to the schedule GUI input 500 and module clock 307, that it istime to begin a sample process 701. The normally closed fill valve 233is then opened 703 for the pre-set Open Valve period OVP and the valveis then allowed to close. After the Open Valve period has beencompleted, the Holding Period timing begins and lasts for a pre-setperiod of 1 minute for example. When it is determined that the HoldingPeriod has been completed 705 and measurements have been taken by theprobes 205-209, then the pump 235 is turned ON for the Pump ON Period707 after which the pump is no longer powered ON and the processingreturns to monitor the clock 307 and schedule 513 for the next scheduledsampling time 711. This processing may be implemented in softwareprogramming stored in the memory unit 305 of the sampling module 221 orin firmware or hardware and implemented on the circuit board 231 of thesampling module 221.

The method and apparatus of the present invention has been described inconnection with a preferred embodiment as disclosed herein. Thedisclosed methodology may be implemented in many different specificembodiments to accomplish the desired results as herein illustrated.Although an embodiment of the present invention has been shown anddescribed in detail herein, along with certain variants thereof, manyother varied embodiments that incorporate the teachings of the inventionmay be easily constructed by those skilled in the art. Portions of thedisclosed methodology may also be implemented solely or partially inprogram code stored on a CD, disk or diskette (portable or fixed), orother memory device, from which it may be loaded into memory andexecuted to achieve the beneficial results as described herein.Accordingly, the present invention is not intended to be limited to thespecific form set forth herein, but on the contrary, it is intended tocover such alternatives, modifications, and equivalents, as can bereasonably included within the spirit and scope of the invention.

1. A method for using water measuring probes of a water sensing deviceto measure predetermined characteristics of water proximate to saidprobes, said method comprising: providing a water-sealed samplingchamber enclosing said probes from said proximate water; and controllingan amount of water in said sampling chamber whereby water is only incontact with said probes when said probes are measuring saidpredetermined characteristics of water in said sampling chamber.
 2. Themethod as set forth in claim 1 wherein said sampling chamber is ventedto outside air to allow water to selectively flow into and out of saidsample chamber when said water sensing device is under water.
 3. Themethod as set forth in claim 2 wherein said water flow into saidsampling chamber is controlled by operating a valve device.
 4. Themethod as set forth in claim 3 wherein said valve device is normallyclosed and selectively opened to allow water into said sampling chamberat predetermined times.
 5. The method as set forth in claim 4 andfurther including selectively evacuating water from said samplingchamber after said probes have completed measuring said predeterminedcharacteristics of water in said sampling chamber.
 6. The method as setforth in claim 5 wherein said sampling chamber is evacuated using aselectively operable pump device.
 7. The method as set forth in claim 1and further including selectively evacuating water from said samplingchamber after said probes have completed measuring said predeterminedcharacteristics of water in said sampling chamber.
 8. The method as setforth in claim 7 wherein said sampling chamber is evacuated using aselectively operable pump device.
 9. A medium within a control system,said medium containing programmable elements, said programmable elementsbeing selectively programmable to control presence of water in asampling chamber of an associated water sensing device, said watersensing device including one or more water measuring probes enclosedwithin said sampling chamber, said probes being selectively operable formeasuring predetermined characteristics of water in said samplingchamber at predetermined times, said programmable elements beingprogrammed to selectively generate program signals, said program signalsbeing operable for controlling a water input device and a water outputdevice for said sampling chamber whereby water is only in contact withsaid probes when said probes are measuring said predeterminedcharacteristics of water in said sampling chamber.
 10. The medium as setforth in claim 9 wherein said medium is a memory unit coupled to controlcircuitry on a circuit board, said control circuitry being selectivelyoperable for accessing said memory unit in controlling operations ofsaid water input device and said water output device.
 11. The medium asset forth in claim 9 wherein said water sensing device further includesmeans for selectively connecting said water sensing device to anexternal computer system, said computer system being selectivelyoperable for providing a graphical user interface (GUI) on a displaydevice of said computer system, said GUI being operable for enabling auser to input selected values related to said controlling of said waterinput device and said water output device.
 12. The medium as set forthin claim 11 wherein said selected values include a time period duringwhich water is allowed to enter said sampling chamber.
 13. The medium asset forth in claim 11 wherein said selected values include a time periodduring which water is held within said sampling chamber.
 14. The mediumas set forth in claim 11 wherein said selected values include a timeperiod during which water is evacuated from said sampling chamber. 15.The medium as set forth in claim 11 wherein said GUI further includesmeans for selectively synchronizing operations of said water inputdevice and said water output device with operations of said watermeasuring probes.
 16. An attachment for use with a water sensing device,said water sensing device including measuring probes for measuringpredetermined characteristics of water proximate to said water sensingdevice when said water sensing device is immersed in a body of water,said attachment comprising: a sampling chamber arranged to be attachedto said water sensing device to enclose said measuring probes of saidwater sensing device in a water-tight configuration; and control meansfor controlling presence of water in said sampling chamber whereby wateris only in contact with said probes when said probes are measuring saidpredetermined characteristics of water in said sampling chamber.
 17. Theattachment of claim 16 wherein said control means further includes; awater input device for selectively controlling water flow into saidsampling chamber; a water output device for selectively controllingwater flow out of said sampling chamber; and an electronicallyprogrammable control means for selectively operating said water inputdevice and said water output device.
 18. The attachment as set forth inclaim 17 wherein said electronically programmable control means furtherincludes memory means, said memory means containing input data accessedby said control means for controlling times of operation of said waterinput device and said water output device.
 19. The attachment ass etforth in claim 18 and further including electrical connection meansarranged to provide an electrical connection to an external computersystem, said external computer system including means for displaying agraphical user interface (GUI), said GUI further including means forenabling a user to input times of operation of said water input deviceand said water output device.
 20. A water sample measuring apparatuscomprising: a water sensing device, said water sensing device includingmeasuring probes for measuring predetermined characteristics of a watersample when said water sample measuring apparatus is immersed in a bodyof water; a sampling chamber enclosing said measuring probes, saidsampling chamber being water sealed from said body of water to preventwater from entering said sampling chamber; and means for controllingpresence of water in said sampling chamber whereby water is only incontact with said measuring probes when said measuring probes aremeasuring said predetermined characteristics of water in said samplingchamber.